Steam-engine.



R. G, STEVENS. STEAM mews.

APPLIOATION TILED SEPT. 26,1313.

Patented Mar. 16, 1915.

witnesses,

fofl 11'- NIT S A ES PATENT onnicn mnnn'r c. "srnvnns or PENNSYLVANIA, ASSIGNQR T0 SKINNER ENGINE OQMPANY, OF ERIE, PENNSYLVANIA, A CORPORATION OF PENNSYLVANIA.

gines; and I do hereby declare the following to be afull, clear, and exact description of theinvention,.such as will enable others skilled in'the art to which it appertains to make and use the same, reference-being had to the accompanying, drawingsyan'd to the letters of reference marked thereon, forming part oftl'iisspecificationi,

Myinvention relates to steam engines and I particularly: to that type of steam engine in which steam is permitted to exhaust from the cylinder at a point removed longitudinally from the intake ports whereby the partially cooled steam, during the exhaust period, is not forced against the hotter portions of the cylinder. 1 This ype is com monly called the uniflow type. Engines of: this iinifiow type are adapted for use in combination with asteam bondenser wherein a partial vacuum in the exhaust is. maintained, which is communicated, to the en- .gine cylinder upon the opening of the exhaust ports by the piston, andupon the return stroke of. the piston, afteri the closing of the exhaust ports thereby, %the partial vacuum in the cylinder must be. converted to pressure before the clearance, insepar'ably incident to engine construc.t10n,i1s properly filled preparatory to the admission of steam thereinto. When, however, engines of this type are designed to be used Without a con denser, auxiliary exhaust ports'iare located between thefsteam intake ports fand the exhaust ports, so that compression commences only after such auxiliary exhaust ports are closed. Heretofore it has been customary to provide engines of this type with a valve for opening and closing each intake port, and each auxiliary exhaust port,' thereby necessitatizfg the employment of four valves,

and their accompanying actuating, gear. It is also customary, when high efficiency is required, to provide the cylinderhead ls and end portions of the cylinder of uniflow engines with steam ackets, in order'that the highly heated inflowjng steam will not im-. mediately condenseon the internal surface of the cylinder, thereby impairing the efficiency of the steam after it enters the cyl- STEAM-ENGINE.

. Specification of Letters Batent. Patented blag. 16, 1915;

Application flied September as, 1913. sria1m.791,993. J

for the reception of live Steam. There are f steam inlet ports a a, located adjacent each Side, of the division wall A; and ad required, a circumferential steam chamber;

(1 around the central portion-of thei-cyll inder. In such cases, one side of the st jacket is exposed to the atmosphere and the heat radiations therefrom are lost, lom shows itself in increased consump't' "offuel. V y It is the obj eat of my invention, therefore, to soconstruct a steam engine of the uniflo y, type, as toovercome the difiiculties and (oh jections heretofore experienced in thefiop' struction and operation of 'unifiow engines 65 and I accomplish this by constructingQthe, engine so asto have a central steam admis i sion, With exhaust at the ends 0f.tlie cyl inder, which enables niefto economicall vsi utilize heat from the steam flowing towardflf the inlet ports of the cylinder, to maintain;

those portions of the cylinder adjacentato; the stem inlet ports, at e maximumdegnee;

of heat without the aid pf end j ackets A1189 1' that all of the valve operatedv ports leading;

from the interior ofsuch an engine cylindei-., r

' constructed in accordance with the centralii steam and end exhaust principle, as herer ,w. inafter described, may be adapted\ to ,thet use. of multiple valves, if desired. ,7 Other, features of my invention wil lz'apw pear hereinafter in the specification, ands: are illustrated in the accompa ing draw lug in Which: M 1 5*90 Figure ,1, is a longitudinal, horizontal section on the line X-X in Figs 2 and F ig. 2, is a transverse section on the line 5 yg in Fig. 1. Fig. 3, is a transverse sec -2 a: tion on the line zz in Fig. 1. 1 In these drawings, A, indicates a stea engine cylinder provided with a central i vision wall A, having a chamber a, therein also provided in the wall of the cylinder jacent to each end of the cylinder A, tlier are provided main exhaust ports B and B" which communicate with circumferentia exhaust chambers B, with which an exhaust f pipe Bi, communicates. I also revidawheirinder A, jar the purpose of extendifig the provide auxiliary exhaust ports C C, which are located between the steam inlet ports a, and exhaust ports B, and B, at such points as may be found best adapted to secure the results desired. 1 have found that a (lesirable location at which to place these auxiliary exhaust ports, is at substantially two thirds of the distance between the main exhaust ports B and B, and the steam inlet ports a; but. others may find it desirable to vary this location.

The division wall A, is provided with'an opening therethrough, which is provided with a stufiing-hox mechanism I), through which a piston-rod E, passes and upon the piston-rod E, Isecure pistons F, and F, one on each side of the central division wall A. Upon the side of the cylinder A, I provide a valve-chest G, which communicates with the central steam chamber a, in the division wall A, and with the steam intake ports a, and auxiliary exhaust ports C, and C. A passage 9, is also provided from each end of the valve-chest (i, to the exhaust chambers B, at each end of the cylinder A. The valve chamber G, is pro-' vided with a valve seat surface G, on the inner wall thereof; through which the auxiliary exhaust ports C, and U, the steam inlet ports a, and the central steam chamber (I, enter thercinto, and is also provided with the usual valve-chest cover G Upon the valve-seat surface G, I place a slide valve H, preferably of the semi-balanced, expanding type adapted to alternately close the steam inlet port a, and open the auxiliary exhaust port C, at the left hand end of the cyiinder, and open the steam inlet port a, and close the auxiliary exhaust port C, at the right hand end of the cylinder, while not at any time closing the opening from the steam chamber (1., in the division wall A, inter the interior of said valve. The valve ll, is provided with the usual valvestem H which operates through the usual stufiing-box mechanism 9, and is connected with the eccentric mechanism (not shown) of the engine, in the usual manner.

The ends-of the cylinder A, are closed by means of heads J and J, the head J, being provided with stuffing-box mechanism 7', of usual and ordinary construction. These cylinder heads are of no importance to the successful operation of the engine when used as a non-condensing engine, but when the engine is used as a condensing engine, they serve to maintain the vacuum incident to It}: condensing of steam in an inclosed chamr. From the ends of the cylinder A, adjacent a to each head there is a relief port K, wliich communicates with the exhaust, as shown in broken lines in Fig. 1, for the purpose of preventing any back pressure between the pistons F and F, and the cylinder heads J and .l, and to carry oii' any vapor which might escape around the pistons. It will be noticed that the sum of the circumferential area of the two pistons F and F, is substantially equal to the circumferential area of the piston in the ordinary type of uniilor; central exhaust engine.

The steam chamber 'a, in the division will A, is provided'with a radial web a, (see Fig. 3) which causes steam admitted through the steam inlet opening a, to make a complete circuit of the chamber a, before entering the valve H, in the valve-chest G,

thcreby thoroughly and continuously heating the division wall A, and the portions of the cylinder A, adjacent thereto," thereby preventing condensation within the cylinder upon those portions of its interior surface. 7

In the operation, steam is admitted into the chamber a, through the opening a, and from thence into the valve H. In Fig. 1, the \alve H, is shown as 0 ening the steam inlet port a, to adinit steam behind the piston F, to move he pistons F and F, and piston-rod E, 'toward the right. the p ston the auxiliary exhaust port 0, is closed by the valve and the auxiliary ex haust port C, is opened. Steam follows the pision'F, at a proximately throttle pressure until the va ve H, cuts it ofi' in the usual manner, after which it expands and its pressure 1s reduced Ulltll it is released by the piston F, passing'and uncovering the main exhaust ports B, at the end of the stroke. Under certain conditions ofp 'on or adjustment, the valve H. may o he auxiliary exhaust C, slightly before the piston F, passes the main exhaust port B"; but the exhaust action of the steam remains practically the same. During this stroke of the piston F, the steam is exhausted from the Y right hand side of the piston F, through the exhaust ports B and C, until the piston F, has passed and covered the auxiliary exhaust port C, at which time the steam re maining in thespace between the port C, and the head A, is imprisoned'to give the we'll known advantage of compression.

Under certain conditions of proportion and adjustment, the valve H, may close the auxiliary exhaust port C, slightly before the piston F, covers said port. but this will not in any manner alter the advantageous open ation of and the necessity for the auxiliary exhaust port C. Vacuum isprevented from formin on the left hand and right hand sides 0 the pistons F, and F, by reason of the fact that this space is, all times,

During this movement of in communication with the exhaust by means of the ports K. It will be readilvappreciated, however, that while the foregoing description refers particularly to a noncondensing engine, the mechanism is equally operative as a condensing. On the return stroke the above cycle of operations is repeated.

From the'foregoing description, it will be obvious that my invention enables me to construct a steam engine having the advantages of a unifiow engine, equally adapted for condensing and non-condensing purposes, as the auxiliaryports C and C, relieve excessive compression when not operating as a condensing engine. It also enables me to construct asteam engine in which the live steam isintroduced into a central chamber and the surfaces heated thereby are not exposed to the atmosphere, and consequently do not Waste steam by radiation as is the case with central exhaust, end jacketed cylinders, and do not require the same amount of care in jacketing to utilize the maximum degree of heat in the engine. It also enables me to eliminate the complicated valve gear accompanying the use of multiple valves, as I can employ a singlevalve and obtain the beneficial results accom lished by the ordinary central exhaust uni ow engine with four valves.

Having thus fully described my invention so as to enable others to construct and utilize the same, what I claim as new and desire to secure by Letters-Patent, is

1. In a steam engine the combination of a cylinder having a steam inlet port at one end and steam exhaust ports at the opposite end thereof, a piston in said cylinder adapted to control the exhaust from said cylinder, a valve mechanism communicating with said inlet port, a hollow head closing said cylinder at the steam intake end thereof having a steam inlet opening thereinto, and a steam passage therefrom to said valve mechanism, a radial division wall in said hollow head extending from the centralportion to the periphery thereof between said inlet. opening and the passage to said valve mechanism, and means to operate said valve mechanism, substantially as set forth.

2. In a steam engine, the combination of a pair of cylinders in tandem each having exhaust ports adjacent to their outer ends, and each having steam inlet ports at their inner ends, valve mechanism communicatin with said inlet ports, a hollow division wa between said inlet ports having a steam inlet opening thereinto and a steam passage therefrom into said valve mechanism, a radial division wall in said hollow wall extending from the central portion to the periphery thereof between said inlet opening and said steam passage to said valve mechanism, convnected pistons in said cylinders adapted to control the exhaust from said cylinders, and means to operate said valve mechanism, substantially as set forth.

3. In a steam engine, the combination of a cylinder having steam inlet ports in 'the intermediate portion thereof, main exhaust ports adjacent to the ends thereof, and auxiliary exhaust ports in the wall thereof between said steam intake ports and the main exhaust ports, a division wall between said steam intake ports, a piston-rod therethrough, pistons secured on said piston-rod at each side of said division wall, a valvechest with which said steam inlet ports and said main exhaust and auxiliary ports communicate, and a valve therein adapted to cover and uncover said steam inlet ports and said auxiliary exhaust ports, substantially as set forth.

4. In a steam engine, the combination of a cylinder having steam inlet ports in its intermediate portion thereof, main-exhaust ports adjacent to the ends thereof, and auxiliary exhaust ports in the wall thereof between said steam intake ports and said main exhaust ports, a division wall between said intake ports having a steam chamber, a piston-rod therethrough, a piston secured thereon at each side of said division Wall adapted to cover and uncover said main exhaust ports, and valve mechanism adapted to open and close said intake and auxiliary exhaust ports, substantially as set forth. p

5. In a steam engine, the combination of a cylinder having steam inlet ports in the intermediate portion, main exhaust ports adjacent to each end thereof, and auxiliary exhaust ports in the walls of said cylinder between said steam inlet ports and main exhaust orts, a division wall between said steam inlet ports, a piston-rod extending through said division Wall pistons secured on said piston rod and adapted to cover said main exhaust ports and said auxiliary exhaust ports during the interval of passing the same on its reciprocations, and valve mechanism adapted to alternately open said intake ports, and alternately open said auxiliary exhaust ports, substantially as set forth.

6. In a steam engine, the combination of a cylinder having steam inlet ports in its intermediate portion, main exhaust ports adja 7 t xhaitt ports, connected pistons in the ien i\""li\& cylinders, and a single valve controlling said inlet and auxiliary exhaust ports, substantially as set forth.

8. in a steam engine, the combination of a pair of cylinders in tandem, with a live steam space therebetween, each cylinder ha ving a main exhaust adjacent to its outer end,

an inlet port at its inner end and an art iliai'y exhaust port in the wall thereof, lie t een said main exhaust and inlet steanrchest at one side of said cylinders communicating with said live shx-un space, a slide valve adapted to receive steam from said live-steam space and control said inlet and auxiliary exhaust ports in both of said -'-\'linilers. and connected pistons in said cyl inders controlling said main exhaust poms, substantially as set forth.

In testimony whereof I ailix my signature, in presence of two witnesses.

ROBERT C. 'S'IEVEUS. \Vitnesses H. M. STURGEON, P. V. GIFFORD.

ports, a B 

